Jeffrey LewisBritain's Independent Deterrent

Sorry for the light blogging of late. I got a chuckle out of this story:

US firms now control UK’s nuclear weapons plant

LONDON (AP) — Britain’s government said Friday that a state-owned nuclear group has sold its stake in the company that manages the U.K.‘s atomic weapons research center, bringing the facility under the control of U.S. companies.

British Nuclear Fuels PLC has sold a one-third share in Britain’s AWE Management Ltd. to Jacobs Engineering Group Inc, based in Pasadena, California. AWE Management has a contract to operate the government-owned Atomic Weapons Establishment, which has facilities in Aldermaston and Burghfield in southern England, through 2025.

The sale means that operations at the center, which makes and maintains warheads for Britain’s nuclear missiles, is now under the control of U.S. companies.

I think it comes as a shock to most people on either side of the Atlantic when they learn how much the UK depends on the United States for its nuclear deterrent. Even I was a little taken aback during my visit to Aldermaston when Don Cook, the Managing Director of the Atomic Weapons Establishment, began to address us in his flat American accent.

I thought “Whiskey Tango Foxtrot? Couldn’t they have found someone British?”

After a couple of days at the AWE, and a tour of the lovely historical collection, I accepted the reality that, no, the United Kingdom does not in any way, shape, or form have an independent nuclear deterrent.

I mean no disrespect to all the people at Aldemaston who endure the nightmarish hell of living in and around Basingstoke to keep their country safe from … well, anyway. And I understand the need for the polite fiction given political debates in the United Kingdom, but the UK suffers when US policymakers buy into London’s public relations strategy.

The fact that stunned me was the model, in the historical collection, of Red Snow — the UK’s first deployed thermonuclear weapon. (Forget Green Grass)

Red Snow is an “Anglicized” version of the US Mk-28. (Anglicized is the nice way of saying “copied”.) The first thing you observe about the the bomb is that compact little thermonuclear device is packaged into a GINORMOUS bomb casing.

The mockup at AWE is a cut-away, but this image from the Nuclear Weapons Archive gives you the idea.

The problem, we were told in the historical talk, was the UK was unable to manufacture the Mk28 to the original specifications.

One implication was that the bomb was too large for the US casing and had to be placed in reused Yellow Sun bomb casings. Another was that the designers had little confidence in the warhead without nuclear testing — which was a problem since the warhead was deployed during the 1958-1961 test moratorium. (I suspect it was eventually tested )

I was able to track down the first story, but not the second — until I noticed that AWE posted it on their website!

The British decided to produce a megaton yield American warhead design under the code-name ‘Red Snow’. The equivalent British device needed more development and more nuclear tests – not possible because of an agreed pause in testing by the three nuclear powers.

However, certain aspects of the American design did not meet the British Ordnance Board Requirements. Modifications were embodied and trials carried out in Australia. The warhead would no longer fit the original American bomb casing and a much larger and heavier British one had to be used.

Well, that’s honesty for you. (In their defense, I think they used a different high explosive.)

The UK has executed three designs since Red Snow — Anglicized variants of the B61, the W59 and the W76.

British Nuclear Weapons

British Desig. Delivery US Desig. In service
Red Snow Yellow Sun Mk.2, Blue Steel Mk28 1961-1966
WE.177A-C Gravity Bomb B61 1966-1998
RE.179 Polaris SLBM W59 1968-1982
ET.317 Polaris SLBM (Chevaline) W59 1982-1996
Unknown Trident SLBM W76 1994-present

Author estimates. I could be wrong.

Presumably AWE does not make FOGBANK, SEA BREEZE or other speciality materials in the W76 — which basically means that UK decision-making about life extension for the Trident warhead depends entirely on the W76-1 Life Extension Program and/or whether the US builds WR1.

They must have been crapping Scotch Eggs when we thought we might not be able to make FOGBANK.


  1. Carey Sublette

    “how muck” indeed! A Freudian typo?

  2. Rwendland (History)

    Spot on Jeffrey, that the UK has used US design information for a long time. And now the UK Trident warhead uses “certain warhead-related components” supplied by the U.S. and some of the fissile material used was purchased from the U.S, so the dependency is now very high. (see 1987 NAO report Ministry of Defence and Property Services Agency: Control and Management of the Trident Programme.)

    But to say “copied” is way too simple, indeed wrong, for pre-Trident warheads at least.

    For example the WE.177B warhead (developed before the WE.177A, which used a different boosted warhead) had a British primary and a secondary based on the W-59 – so as to avoid using PBX-9404 explosive, considered by the British to be unsafe.

    A former AWE physicist, Brian Burnell, has written up a lot of this detail, based on declassified info he tracked down in the Public Records Office. The whole thing is worth reading, but a taster of the complexity is:

    WE.177B had a thermonuclear warhead, comprising two parts. The primary was KATIE … based on a British design known as CLEO, earlier known as Super Octopus, intended as the thermonuclear primary for RE.179, a British warhead for the RAF version of the cancelled Skybolt air-launched ballistic missile. The secondary (or fusion element) of RE.179 was based on the US W-59 warhead and was known by the British codename of SIMON. However, the W-59 primary used PBX-9404, a plastic-bonded-explosive, considered by the British to be unsafe. The US W-44 primary was replaced with a British primary developed from CLEO, that evolved into KATIE, that did not use the shock-sensitive PBX-9404. When Skybolt was cancelled the fusion secondary of RE.179 was adapted with KATIE to become WE.177B (also referred to as Weapon X) and in a smaller version, the British ET.317 warhead for the Royal Navy’s Polaris A3T.

    Note that many of Brian Burnell footnotes are photos of former secret documents he tracked down and photographed at the Public Records Office. I’ve not gone through this in detail, but it looks like wonderful, but largely unrecognised, work.

    Brian Burnell’s rather interesting comment on the US/UK relationship as a shared experience is:

    Some writers made the assertion that because the British conducted so few full-scale nuclear tests, WE.177 was unlikely to be an indigenous design. That it must, by a curious extension of that logic, be an American design, the closest being the B57, while failing to understand that the WE.177 fission element was one of a ‘family’ of designs, deliberately similar, intended to produce a ‘common design’, usable with only minor changes, in a variety of applications from Skybolt, Polaris, Blue Water and WE.177. As it indeed was, and so a single series of only four full-scale underground nuclear tests were necessary, plus one failed test. There were four other [nuclear] ‘effects’ tests conducted in the US, and numerous non-nuclear ‘scaled’ tests in the UK. Hardly a small testing programme for a single fission device. In fairness to those writers, it may not have been so apparent then as now, after numerous declassifications of archived documents.

    Such speculation also fails to take into account the cultural and financial differences between the US and British nuclear programmes. The early US programme was over-reliant on full-scale testing because of the extreme urgency attached to its very large programme. There are instances of poor design directly attributable to a poorer theoretical understanding of the physics, and an empirical design approach. The fission primary of the W-28 being one example of design flaws attributable to an imperfect theoretical understanding. On the other hand, the British, with fewer resources, and always short of cash, employed their meagre resources to better effect, with a better understanding of the theory that underpinned their efforts. They also benefitted from the shared US test data, as the US benefitted from equally valuable British know-how. That shared know-how, coupled with British experience and greater theoretical understanding was one factor that contributed to an American desire to complete the 1958 Bilateral, or Mutual Defence Agreement. The US understood that they had much to gain from the British, as the British also gained. It was a shared experience, not a one-way street.

  3. FSB

    Who is about to attack UK with nuclear weapons? Hahaha!

    For that matter, who is about to attack US/Russia/France/etc. with nukes? Frickin’ Oldthinkers doubleplus un-understand deterrence.

    OK, so the weapons do serve some kind of ill-defined vague deterrent purpose (against who? against what action?) but the same “deterrent” could be had for 5 weapons for each NWS. And we actually would have some $ in our budget.

  4. Azr@el (History)

    Fogbank? what’s that? Cough…metallic oxide aerogel..cough..density controlled by ACN..cough…castable..cough..
    after treatment can be machined further..cough process causes cancer..cough..

  5. Andreas Persbo

    I believe the change in explosives had something to do with a truck blowing up and the ordinance board having a subsequent fit.

  6. Brian Burnell (History)

    Like the photo of Red Snow. Pity its not the real thing tho’ but merely a simplified, cleaned up model intended to mislead journos and other jerks.

    Look at the height of the roadside kerb compared to the model. About 4 inch high I’d say, wheras the Real McCoy Red Snow measures ~ 4 feet dia. And the uncropped original photo showed a tyre mark on the concrete that would measure 3 feet wide if the bomb were real.

    Nice try tho’.

    Andreas. Don’t know about a truck blowing up, but the OB had an aversion to overly shock-sensitive HE formulations and had long experience of how they invariably went pear-shaped. Only much later in the day did the US discover that insensitive HE was the way to go.

    A happy New Year to you’all now.

  7. Brian Burnell (History)

    I’m not a physicist, now or formerly.

  8. Jeffrey Lewis (History)


    Well, as I said, I was able to see a full-scale mock-up in the historical collection at AWE, but we were prohibited from taking pictures (or sketching).

    The image I posted generally conveys the difference between the relatively compact thermonuclear weapon and the much larger bomb casing — even if it is a scale model.

    By the way, your site — in particular the WE.177 history — is fantastic.

  9. Rwendland (History)

    Brian, sorry I misremembered you as physicist rather than an engineer.

    Re sensitive explosive. Your PRO document (TNA AVIA 65-1050-E87a-p2) photo records that the U.S. Wee Gnat – which I think is the Davy Crockett W54 warhead – used somewhat sensitive explosive and “There had been accidents with it in the US although these accidents had not resulted in a nuclear yield.” Don’t if that was PBX-9404, but it is surprising a somewhat sensitive explosive should be used on such a small weapon that could easily be carelessly handled on the battlefield.

  10. Brian Burnell (History)

    Don’t know off the top of my head what the HE was but will look it up and post it later. The history of the UK programme is littered with similar versions of the same issue; the lower standards the US adopted to HE shock-sensitivity. But that happens when there is extreme pressure for time. Corners are cut. Mistakes are made in the haste to meet target dates. The British were more laid back perhaps. But I remember one document where a Whitehall bureaucrat was listing the options for a warhead for the first UK Polaris warhead. After listing various options recommending a UK design of primary, because it was safer and used HE that was less shock-sensitive than that used in the US W-58 warhead used on the USN Polaris. He dismissed using the W-58 warhead on UK Polaris for that very reason, and then subtly alluded to the fact the USN (less safe) warhead was based a few miles along the River Clyde at the Holy Loch from the Royal Navy’s [safer] warheads at their sub base at the Gareloch. The message to Minister’s that they should be aware of the political fallout should that news ever reach the public domain was unmistakable. You can read the original here link text

  11. Brian Burnell (History)

    Chuck Hansen’s Swords of Armagedden vol8 p171 lists the Hardtack 1 test of the Sequoia device as possibly a prototype of the XW-54 Gnat device, and lists it as having HE of PBX.9404. The same HE as used in the W-58 considered unsafe by the UK Ordnance Board.

    Swords is a reliable source, but unfortunately not online.

  12. Brian Burnell (History)

    Ref the W-54 warhead.

    Chuck Hansen’s Swords of Armageddon vol 8 p171 Table A-1 states that PBX 9404 was the HE. This is the same HE that was rejected by the British for use in their warheads because they considered it unsafe.

  13. Brian Burnell (History)

    Ref the mismatch between the size of the bomb casing and the Red Snow warhead commented on above.

    The National Archives AIR 2/17322 E8A p2.6 verbatim.
    “Whilst on this proposal, the question of adopting the US Mk.28 [bomb casing] in one or more of the tactical configurations was raised. Mr Challens [Director AWRE] said he could not recommend this as there were difficulties over the strength of the Mk.28 case that even the Americans wished they could eliminate by an increase in outside diameter. Red Snow had the larger diameter [compared with the US W-28 warhead] and hence could not be used with Mk.28 nose and tail ends. We should have the same ballistic trials to face if we decided to engineer Red Snow as a free-falling bomb as we would have if … “

    This is essentially the reason why Red Snow was inserted into the existing British strategic free-falling bomb case Yellow Sun. It was carried internally, only in V-bombers, so its size was not a hindrance, and its ballistic characteristics were already well known. This combination saved development time and cash, and the UK only envisaged using Red Snow in a high-altitude, free-falling scenario. That they failed to anticipate that the days of the high-speed, high-altitude manned bomber were ending, and with that the usefulness of this casing, is another story.